Angela Rayner has been forced to deny any immediate plans to challenge Keir Starmer for the Labour leadership, amid feverish speculation at Westminster as voters in Batley and Spen go to the polls.
Labour still has hopes of winning the hard-fought byelection; but many MPs are already discussing what might happen if they were to lose it.
The Guardian understands that allies of Rayner did make tentative approaches to potential supporters after May’s Hartlepool byelection, which Labour lost, and believed at the time they could have mustered the 40 MPs necessary to launch a challenge.
But they insist she does not want to stand now, preferring to try to shape Labour policy, and they are concerned about the risk to her reputation if she wields the knife against a sitting leader.
Responding to reports that she is preparing to overthrow Starmer, who has only been in post for just over a year, Labour’s deputy leader tweeted it was “news to me”.
Senior sources at the Unite trade union also denied they had had any approach from potential leadership candidates, insisting the only race they were focused on was the one to succeed Len McCluskey.
An aide to Rayner said: “Angela is focused entirely on her jobs. She has set out radical economic policy on the future of work and has led the way hammering Hancock and the government over private emails, dodgy contracts and sleaze.
“She is also perfectly capable of speaking for herself and doesn’t need anyone to claim to speak for her.”
However, underlining the continuing bad blood between the deputy leader and Starmer, Rayner’s supporters believe the stories are being promulgated by outriders of the Labour leader, hoping to undermine her by making her appear disloyal.
If she did decide to launch a bid, Rayner could not automatically count on the backing of the left of the Labour party, with some members of the Corbynite socialist campaign group suspicious of her.
Richard Burgon, the group’s secretary, ran against Rayner for the deputy leadership last year and is known to be sceptical about her credentials as a leftwinger.
However, MPs on the left of the party have become increasingly despairing about Labour’s direction and prospects of winning the next general election under Starmer.
They fear Blairite figures, including Peter Mandelson, have significant sway over the leader’s office and that if McCluskey is succeeded at Unite by the more moderate Gerard Coyne, the balance of power on Labour’s ruling national executive committee could change.
They fear that could allow a change to the leadership rules, diminishing the influence of grassroots members – the factor that allowed Jeremy Corbyn to become leader in 2016. Blair recently wrote that Labour needs “total deconstruction” to win power.
Starmer’s team deny Lord Mandelson has any formal role, and are preparing to announce fresh appointments in the coming days after a number of key figures were moved aside.
The historic loss of the Hartlepool seat was followed by a standoff in which Starmer sought to remove Rayner from her posts as party chair and national elections coordinator and she dug in her heels.
Rayner emerged with several new job titles, including shadow secretary of state for the future of work.